Production of vat dyestuffs



Patented New Ed,

UNITED STATES PATE roFHcr;

WILFRED M. MURCH, OF HAMBURG, AND

wINFRnn a; CAUWENBERG, on BUFFALO,

NEW YORK, ASSIGNORS TO NATIONAL ANILINE & CHEMICAL COMPANY, INC., NEW YORK, N. Y.,' A CORPORATION OF NEW YORK I :enonnorron or No Drawing. Application and ma 26,

This invention relates to the production of new coloring matters which are of value as vat dyestuffs. It includes the dyestufi's,

their manufacture, with the dyestutl's.

Inthe fusion of benzanthrone with caustic and the material dyed potash in the presence or absence of a reducing agent, and in the presence or absence of an inert diluent or solvent, there is produced a crude composite product which is made up in part (about to 60 percent) of a 'vatable dye known as dibenza'ithrone' and in part (about 60 to 40 percent) of a non-vatable by product, the former being soluble and the latter being substantially insoluble in a dilute alkaline sodium hydrosulfite' solution. It is well known that the non-vatable by-product is of little practical value for direct use as a dye although it appears to go on to the fibre to some extentfrom colloidal suspen-.

- able toy-product with an oxidizing agent, particularly with a mild oxidant such as, for

example, an aqueous solution of sodium hypochlorite, that it can be converted into a new composite mixture or product which 1S sol- 1- i uble', or is partly soluble, in an alkaline hydrosulfite solution, givinga red violet vat which dyes cotton dull violet shades. Uponnitia tion, this new composite mixture yields a product which is substantially completely soluble in an alkaline sodium hydrosulfite solution givinga violet blue vat which dyes vegetable fibres olive shades which are changed to brown shades on treatment with sodium hypochlorite while the nitrated unoxidized, non-vatable initial by-product gives a product which is only partly soluble in an alkaline hydrosulfite solution to yield a vat which dyes cotton dull, weak greenish gray shades. In the dry state, the new composite mixture resulting from the oxidation of the original no'n-vatable by-product is a dark powder insoluble in water and in dilute acids VAT DYESTUFFS 1926. Serial No. niece.

but soluble in concentrated sulfuric acid giving a blue-black colored solution. 7

\Ve have further found by treating the crude composite product comprising the vat- .able dye (i. e., dibenzanthrone) and the nonvatable by-product, and which results f rom the fusion of benzanthrone with caustic alkali, with an oxidizing agent which is cap able of oxidizing the non-vatablc by-product but Whichissubstantially indifferent to the vatable dye dibenzanthrone) that the amount of vatable dye can be increased and parts are by weight.

Ewamplcr A quantity of crude dibenzanthrone in the form of paste and containing 40' parts of dry material comprised of about equal parts of vatable and non-vatable compounds, and preparedby fusing benzanthronewith caustic potash in the presence of dextrine at a temperature of about 220 240 (l, is suspended in 2000-2500 parts water, and 250 parts of a 10 percent sodium hypochlorite solution are added. The mixture is heated and boiled for about one hour, then filtered and the residual dyostufl washed with hot water until free from alkali and soluble colormg matters. It is then dried or made into a paste as desired.

-' The crude composite productthus obtainedis; in the dry state, a blue-black bronzy powder soluble in concentrated sulfuric acid, giving a' clear violet solution. It dyescotton blueviolet shades from a hydrosulfite vat, the ex haust being quite clear and containing comparatively little color. The unoxidized, original crude composite product, on the other hand, dissolves in concentrated sulfuricacid giving a somewhat turbid violet solutlon, and

between the ti with nitric acl crude composite ,a productwhich dyes cotton green shades from an alkaline hydrosulfite vat-,and the exhaust is turbid and contains considerable"colored Ind 'handrthe new d the inltial, crude composite mixture wlth so-.

impurities. Upon treatment with a hypochlorite solution, the green shades are con verted to reddish-black shades. In general, it is'not completely soluble in an alkaline solution of sodium hydrosuliite. One the other vestuft obtained by treating dium hypochlorite gives upon nitration a pro- I preferred results.

duct which is substantially completely soluble in a solution of sodium hydrosultite from which it dyes cotton green shades. The exhaust is substantially clear and contains little color, and upon'treatment with hypochlorite the green shades are changed to greenishblack to jet black shades. v I

In the above example, the-proportipn and nature ot-the oxidant as reunite conditions of carrying out the process may be varied over a wide range without departing from the spirit and scope of the invention. instead of treating the isolated crude dibenzanthrone, the alkaline fusion mass may be dissolved or suspended in water andithesol-utionor suspension treated first with a current of air to oxidize the leuco-dye to the dyestuff and then with a current of chlorine until a dyeing of an isolated sample gives the desired shade on cotton. instead 0t sodium hypochlorite, other hypohalites and other oxidants may be used, particularly those adapted to oxidize the non-vatable but notrthe vatable product. Alkaline oxidizingagents'ap'pear to give the it will thus be seen that the present invention contemplates the production of a new vatable dyestufi by treatingwith an oxidizing agent a crude dibenzanthronewhich is composed ot a vatahle (i. e, pure dibenzanthrone) and anon-vatable product. By this treatment, there isproduced a product which can be reduced to a leuco form which can be dis solved in alkaline-sodium hydrosultite liquors to form a vat which exhausts well. T he product is particularlyvaluable as an intermediate in the production therefrom oi nitrated dyestufis having desirable properties. It will be understood that. in the crude dibenzanthrone the proportions of the vatabledye and non-vatable hy-product may be widely difi'erent depending on the purity of the henzanthrone initially used, the conditions of fushion, etc. p

in the following claims, it is understood.

- that the term benzanthrone coin ,ound is used as a generic term to inclu e benzenthronc, or a derivative, homologue. or analogue thereof.

"57c claim:

1. In the production of ccloringm'attcrs,

a process which comprises treating composite product containing a vatablc dye and a iion-vatable byproduct, and obtainable from the fusion of benzanthrone with caustic potash, with a'mild alkaline oxidizing agent.

2. the production of coloring matters, a process which comprises treating with a mild alkaline oxidizing agent the non-vatable bya process which comprises treating with so-.

dium hypochlorite the non-vatable by-pro uct resulting from the fusion of benzanthrone with caustic potash in the presence of dextrine.

a. As new coloring matters, the products which can be obtained by treating with mild alkaline oxidizin agent the non-vatable by-product resulting from the fusion of henzanthrone with caustic potash, said products in the dry state being dark powders insoluble in water but soluble in sulfuric acid with a blue-black color, and from a hydrosulfite dye cotton violet shades.

-5. As new coloring matters, the products which can be derived by treating a composite product containing vatable dye and a nonvatable by-product, and obtainable from the fusion of benzanthrone with caustic potash, with a mild alkaline oxidizing agent; said new products being insoluble in water and dilute acids but soluble concentrated sulfuric acid with a violet color, dyeing cotton blue-violet shades from an alkaline hydrosulfite vat, and which, after nitration, are substantiallycompletely soluble in an alkaline sodium hydrosulfite solution giving vat which dyes cotton green shades which upon treatment with sodium hypochlorite change to black shades.

6. As a coloring'matter, the new product which can be obtained by treating a composite product containing a vatable dye and a nonvatableby-product obtainable from the fusion of benzanthrone with caustic potash, with sodium hypochlorite; said new product being insoluble in water and dilute acids but soluble with a violet color in concentrated sulfuric acid; and yielding iipon nitration a product which is soluble in alkaline hydrosulfite liquors giving a vat which dyes vegetable fibres green shades which are changed to black shades upon. treatment with sodium hypochlorite;

' 7. As a new composition of matter, a vat dyestufi comprising dibenzanthrone a product obtainable treati' with sodium s'ulting' from the fusion of impuie benzenthrone with caustic potash, said product upon nitration yielding a coloring matter :tures.

which dyes cotton from a vat whose dyeings upon treatment with hypochlorite change from green to black shades.

8. Material dyed with a coloring matter of claim-4.

9. Material dyed with a coloring matter of claim 5. t v 10. Material dyed with a coloringmatter of claim 6. v 1

11. Material dyed with the "coloring mat- ;ter ofclaim 7 In testimony whereof we afiix our signa- W'ILFRED M; MURCH. WINFRED J; GAUWENBERG. 

